Northern bedstraw is a good plant for those tricky dry-ish shaded spots. Dry-ish: it does appreciate some moisture, but I've found that with protection from appropriate companion plants it gets by without much supplemental irrigation. It can also tolerate a decent amount of sun if it does get extra water.
 
The delicate little whorles of leaves are probably this plant's neatest feature, but the clusters of tiny white flowers are a nice summer bonus.
 
In our area northern bedstraw tends to grow on the edges of woods and thickets. Plant beneath ponderosa pines, or taller shrubs such as serviceberry and rocky mountain maple. Good companions include sticky geranium, chamisso sedge, slender cinquefoil, wild strawberry, and raceme pussytoes. This species can be vigorous, so put it where you don't mind some sprawling.